I did the 10K Swing Challenge in 12 days last fall (starts here and ends here) and then did 25K swings over the first 50 days of 2023 (some details available here), both with a 28 kg bell, and I found chasing the Time Dragon to be motivating in both undertakings: How quickly could I get to 500 swings?
I never did get 500 unbroken, though—maybe that’s a challenge worth your effort?